The observable region is an approximate indication of the latitude at
which the comet may be seen. Under good conditions comets may be visible
outside this range. The period when visible is for the UK if the comet
is visible from the UK, otherwise for 40 S or the Equator as appropriate.
The last visual observation is as received by the Section, details are often updated on
the basis of observations published elsewhere. Details are
normally fully updated at the beginning of each month, but may be updated more
frequently for comets brighter than 10th magnitude; the date of the most recent partial update,
which may apply to only one object, is
given. Beginners will often find comets fainter than about 7th magnitude difficult to
locate - see below for information on positions and finder charts.

There is to be a Pro-am observing campaign on 46P/Wirtanen in 2018.
There is a brief observing window for UK observers in September which will
be useful for determing the magnitude parameters at this return, but it is
best seen from the southern hemisphere during this period. It
quickly moves into the evening sky in mid November, and could be a naked eye
object in December.
It makes a close approach to Earth on 2018 December 16, passing 0.078 au
from us. It could remain within visual range until March 2019.

The final update on comet predictions for 2018 was posted in 2018 February.
The comet predictions for 2019 were updated in 2018 February. The
preliminary 2020 predictions were
posted in 2017 October.

The Section welcomes observations from all comet enthusiasts, whether members of the
BAA or not. An advantage of joining the BAA is that you can read papers on comets
published in the BAA Journal. The 2017 December Journal included a paper on "The
brighter comets of 2011". Further papers in this series are in press
(2012 - 2014) or under review (2015).

Thanks to the many observers who have sent in
their observations in ICQ format. Imagers are encouraged to reduce their
observations to equivalent visual magnitude (see Project Alcock
) and submit them in this format. Do check the observation files (updated
March 1) to see if what
you sent matches what is there, as I still have to edit some of the submitted records,
particularly the positioning of the DC, which should go in column 56, the position of "m" when tail
length is given in minutes and the focal ratio. If your observations are missing it may be because you have not used the correct format,
which includes ICQ as a key. If you use the Comet Observation Databaseto enter your observations they will be formatted correctly.

Light curves of comets brighter than 10th magnitude or
predicted to become that bright (aperture corrected for potential naked eye
comets) [click on thumbnail to get the full scale image, updated on 2018 March
1]. The dotted lines represent 99% confidence limits. 2016 M1.

Longer period ephemerides are given here for planning purposes for comets
that may reach naked eye brightness. All are for the UK. The ephemerides give B1950 and J2000 positions.
Modern star charts use J2000, but older atlases will use B1950. The predicted magnitudes are
extremely uncertain.

None at present

Planning aids and information for forthcoming comets

Comets reaching within three degrees of 180° opposition
[updated 2013 December 31]

Comets reaching within three degrees of zero phase angle
[updated 2013 December 31]

The MPC also has a
list of the last observation
for all comets. Electronic observers should try and observe any
comets that have not recently been observed according to the CBAT but which
are expected to be within range of their equipment. Negative observations
are also useful. In addition, the MPC has orbital elements for
unusual asteroids, many of
which have cometary orbits.

Orbits etc

The elements and ephemerides from the JPL Small-Body Database Browser
give estimates of the errors, which are often far larger than might be thought from the
accuracy of the elements given by the CBAT. Full details of the latest orbits are available from Kazuo Kinoshita's
Comet Orbit Home Page. I compile orbital elements in
Megastar format for: periodic comets , current comets ,
comets prior to 2005. Most of the more recent elements
include the latest magnitude parameters. The elements are from a mix of CBAT
catalogues, MPC, MPEC, JPL and individual orbit computers.

Predictions for the comets expected to return in
2017 ,
2018 [updated 2018 February 1] , 2019 [updated 2018
February 1] and 2020 [created 2017 October 25]
are published in the BAA Journal in December each year.
This list
[Updated 2017 October 28] gives the period of visibility and maximum
brightness for comets that are predicted to be visible within the next
five years. A few are listed further into the future.
Seiichi Yoshida also has a list
of comets likely to be visible in the next five years.

Observations may be used in the reports on comets
which appear on these pages, in The Comet's Tale and in the BAA Journal.
Guidance on observing is given in the BAA Comet Observing Guide

Visual and visual equivalent magnitude observations should be sent to me at <jds [at] ast.com.ac.uk> in
simple text format.
Visual observers can use
the BAA visual report form
to log observations. To avoid the use of multiple formats the ICQ format, which uses special
keys to code
observation particulars, is now standardised as the one to use for submission and archiving of
observations. The ICQ have not updated their observation keys since 2010, so these additional
keys are suggested for use when submitting observations to the BAA (updated 2017
January 4). Crni Vhr Observatory has launched
the Comet Observation Database which allows entry of observations
in ICQ format, and plots of light curves. Visual observations entered using this system
should be emailed to me at the end of the month. Observations are
usually analysed and sent to TA as soon as possible after the end of the month; any late
observations will be used in subsequent analyses. Observations will continue to be published by Guy Hurst in
The Astronomer
magazine in TA format.
There is also a visual drawing form. The German comet group also has a computer program that will
correctly format observations for the ICQ [2009 December].

Warning I receive a large number of emails
containing viruses or other junk. Please try and make clear that your message is
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Many thanks to those that regularly access this page for your interest.
If you have any comments, suggestions for improvement or find any problems,
please email the visual co-ordinator,
Jon Shanklin, at j.shanklin @ bas.ac.uk.
If you need to phone me, my home number is +44 (0)1223 571250
or my BAS number is +44 (0)1223 221482.
Snail mail will reach
me at the British Antarctic Survey, Madingley Road, CAMBRIDGE CB3 0ET, England.
For information about my work with BAS see my
web page at BAS.